写了一个图片缩放程序,当图片尺寸过大时会报错:
Exception in thread "Image Fetcher 0" java.lang.OutOfMemoryError: Java heap space
解决方法:
在Eclipse里选:Window->Preference->Installed JREs->Edit(选中jre),
在Default VM Arguments里输入-Xms256m -Xmx1024m,表示最小内存256M,最大1G,然后运行就可以了。
程序源码ImageBrowser.java :
import java.awt.Container;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JScrollPane;
public class ImageBrowser extends JFrame {
private static final long serialVersionUID = 1L;
JLabel lab = new JLabel();
JFileChooser chooser = new JFileChooser();
private String filePath;
private int height;
private int width;
private final double ratio = 0.2;
public ImageBrowser() {
initial();
setTitle("Image Browser --- No image");
setSize(600, 400);
setLocation(200, 150);
setVisible(true);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}
public void initial() {
// Create Menu
JMenuBar menuBar = new JMenuBar();
setJMenuBar(menuBar);
JMenu menu1 = new JMenu("File");
JMenu menu2 = new JMenu("Edit");
menuBar.add(menu1);
menuBar.add(menu2);
JMenuItem openItem = new JMenuItem("Open");
menu1.add(openItem);
openItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
chooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
int r = chooser.showOpenDialog(null);
if(r == JFileChooser.APPROVE_OPTION)
{
filePath = chooser.getSelectedFile().getPath();
setTitle("Image Browser --- " + filePath);
spread();
}
}
});
JMenuItem spreadItem = new JMenuItem("Spread");
menu2.add(spreadItem);
spreadItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
spread();
}
});
JMenuItem resumeItem = new JMenuItem("Resume");
menu2.add(resumeItem);
resumeItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
resume();
}
});
JMenuItem largeItem = new JMenuItem("Large");
menu2.add(largeItem);
largeItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
height = (int)(height*(1+ratio));
width = (int) (width*(1+ratio));
lab.setIcon(getFixedBoundIcon());
}
});
JMenuItem reduceItem = new JMenuItem("Reduce");
menu2.add(reduceItem);
reduceItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
height = (int)(height*(1-ratio));
width = (int) (width*(1-ratio));
lab.setIcon(getFixedBoundIcon());
}
});
JMenuItem exitItem = new JMenuItem("Exit");
menu1.add(exitItem);
exitItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
System.exit(0);
}
});
Container contentPane = getContentPane();
JScrollPane sc = new JScrollPane(lab);
contentPane.add(sc);
}
public void spread() {
File file = new File(filePath);
Icon ic = new ImageIcon(file.getAbsoluteFile().toString());
int icHeight = ic.getIconHeight();
int icWidth = ic.getIconWidth();
Container contentPane = getContentPane();
height = contentPane.getHeight();
width = contentPane.getWidth();
if((double)height/width>=(double)icHeight/icWidth)
height = (int)(width*(double)icHeight/icWidth);
else
width = (int)(height*(double)icWidth/icHeight);
lab.setIcon(getFixedBoundIcon());
}
public void resume() {
try {
Icon ic = new ImageIcon(filePath);
height = ic.getIconHeight();
width = ic.getIconWidth();
lab.setIcon(ic);
}
catch(Exception e) {
e.printStackTrace();
}
}
public Icon getFixedBoundIcon(){
double Ratio=0.0; //缩放比例
try {
File F = new File(filePath);
Icon ret = new ImageIcon(filePath);
BufferedImage Bi = ImageIO.read(F);
if(1==1) { // ((Bi.getHeight()>height) || (Bi.getWidth()>width)) {
if (Bi.getHeight()>Bi.getWidth()){
Ratio = (new Integer(height)).doubleValue() /Bi.getHeight();
} else {
Ratio = (new Integer(width)).doubleValue()/Bi.getWidth();
}
File ThF = new File(filePath+"_"+height +"_"+width);
Image Itemp = Bi.getScaledInstance (width,height,Image.SCALE_SMOOTH);
AffineTransformOp op = new AffineTransformOp(AffineTransform.getScaleInstance(Ratio, Ratio), null);
Itemp = op.filter(Bi, null);
ImageIO.write((BufferedImage)Itemp, "jpg", ThF);
ret = new ImageIcon(ThF.getPath());
}
return ret;
}
catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
public static void main(String[] args) {
new ImageBrowser();
}
}